In a gas turbine engine with a multi-stage compressor, a compressed air generated by a compressor is in part used for the cooling of a turbine, for example. The compressed air is extracted from the compressor through a plurality of slits formed in a compressor housing at regular intervals in the circumferential direction so as to prevent a pressure drop in the air extracting zone and the resultant uneven pressure distribution in the compressor with respect to the circumferential direction.
For this purpose, JP 2001-304194 (A) discloses to provide various sizes of slits in order to extract various amounts of compressed air depending on usages of the extracted air. This technique may be advantageous in that a suitable pressure distribution is obtained for various amounts of air to be extracted.
On the other hand, the technique requires that the various sizes of slits are formed integrally in the compressor housing, which complicates design modifications of the slits according to the requirement of change in the amount of air. Also, the slits are defined by different members defining inward and outward portions of the compressor housing. This complicates a dimension control of, in particular, narrow slits for extracting smaller amount of air, which needs elevated size precisions. Therefore, an even pressure distribution may not be obtained within the interior of the compressor.
An object of the present invention is to provide a structure for extracting a part of compressed air generated by a compressor, which makes it easy to control a dimension of the narrow slits for extracting smaller amount of air and maintains an even pressure distribution within the interior of the compressor of the gas turbine engine by a simple arrangement defined therein.